This invention is related to mailing cartons for fragile items such as books, phone records, photo albums, and the like and in particular, mailing cartons which provide protection for the side edges.
It has been observed that books are dimensionally standardized as to length and which but vary considerably as to their respective thickness. Thickness is determined by the number of pages, the thickness of the paper and of the cover, among other factors.
It has also been observed that postal regulations and prevailing standards make obiligatory that the contents within the carton be confined in a snug and shakeproof manner.
In the prior art, in conformance with said requirements, the rectangular mailing cartons for such items were devised to have the top and bottom panels and also the four side wall panels to conform to the dimensions of the contents. Since the basic blanks of such cartons are normally fabricated by means of cutting and creasing dies each variation of the thickness required an individual die. This necessity represents a substantial expense in the cost of such dies and of their storage.
There have been many attempts to provide boxes intended to protect the narrow edges of such objects as books. In the past, it has been common practice to contain books in containers made of corrugated cardboard but having somewhat larger dimensions of length and width than the object contained. Interior packaging is provided to hold the object in spaced relation to the end walls of the container. More recently, the use of recessed-end containers has increased. Containers of this type comprise sleeves having intergral closure flaps which extend inwardly of the container so as to engage the product and to hold it from relative movement with respect to the container. Such arrangements are exemplified by Boytel (U.S. Pat. No. 3,289,824) which discloses such flaps on three sides of a parallel sleeve rectangular container. Shirley (U.S. Pat. No. 2,591,882) and Nehers (U.S. Pat. No. 3,064,875) also disclose the use of end flaps folded in upon itself to form a rectangular cushion.
Johnson (U.S. Pat. No. 3,465,946) and Greene et al. (U.S. Pat. No. 3,485,435) suggest side panels interconnecting larger rectangular panels. The side panels of these containers are so disposed as to form channel-like flanges which terminate inwardly of the outer edges of the rectangular panels. The extension of the outer edges are intended to form a buffer to protect the edges of the book therewithin.
All of these suggestions have a number of difficulties in common. Firstly, the use of a complicated fold enabling the formation of air pockets at the narrow end of such containers invariably results in a variety of pre-scored widths of the container blank. As a result, dies of varying sizes are required in order to score the material from which such cartons or containers are made. With each new book, as might be expected, at least one dimension must change. Thus, while a publisher can hold length and width constant, for example, thickness (i.e., the number of pages) will change from book to book. This requires the manufacturer to maintain a great many dies -- a plurality of each container of a different thickness of book.
With reference to cartons having inwardly-expanding flanges along the narrow edges thereof, such arrangements require different types of scoring. Thus, the inwardly-folded edges must be scored on one side of the container while other folds are scored along the opposed surface. The inward thrust of the narrow flap ends formed with the inward folds tend to injure the book as it comes in contact therwith. This may be particularly seen with reference to the device of Greene et al. in FIG. 4 of the patent referred to hereinabove, in which the inward edges of the flap directly contact the pages of the book. Assembly of such containers is complicated and time consuming.